Steam not launching games - no idea what to do [Solved]

This may not be a Linux specific problem as I had the exact same issue earlier with Windows 7 and it's one of the reasons I installed Linux in the first place.

The specific game I'm trying to play is DayZ but it may not be issue specific to this game. It worked flawlessly untill this point. I had made no changes to anything. Basically when I try to launch the game it starts loading up normally and then just apparently quits and the "Play" button goes back green. No error, no black screen, no freezing or anything. It just stops launching the game.

I've tried checking the integrity of files, deleting downloads catche, disabling steam cloud, removing launch options.. nothing. Almost like it gets blocked by firewall or something. However I feel like it may be an issue with steam itself or then it's a hardware issue (I've got really old PC)

Few things I've noticed that may or may not be related:

• When opening up steam it almost always used to download some updates first and check the integrity of them or something. Now it doesn't. It just opens up Steam. When I click "check for updates" it says everything is up to date.

• The firmware updater shows available updates for my SSD and HDD but no option to update. I also tried with sudo fwupdmgr get-devices but it says "UEFI firmware can not be updated in legacy BIOS mode See https://github.com/fwupd/fwupd/wiki/PluginFlag:legacy-bios for more information."

• In the privacy settings it says "checks failed" and gives me this message:

• I've tried reinstalling Proton BattlEye Runtime but it wont let me uninstall it and says "missing shared content"